JPH0373677B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for cleaning the air vents of the firebox of a black liquor combustion furnace, and more particularly to an air vent cleaning device for a black liquor combustion furnace which allows the air vents to be cleaned sufficiently quickly and automatically. It is.

Pulp for papermaking is usually produced by the kraft or sulfate process, in which wood chips are treated with a boiling liquid containing sodium sulfate and sodium hydroxide. The wood chips and the boiling liquid are boiled in a digester at a predetermined amount of heat and temperature conditions. In the next step in the process, the so-called black liquor, consisting of the spent chemicals and the organic substances separated from the pulp, is processed in a recovery unit to recover the boiling chemicals. Without the recovery and reuse of this boiling chemical, the cost of papermaking operations would be significantly higher. Black liquor is sprayed into the firebox of a recovery furnace where organic substances burn at high temperatures and chemicals are deposited as a bed of char on the floor of the firebox, and the chemical-containing odor substances melted from the deposits are removed. Collect for further processing. At the same time, the heat of combustion is used to generate steam in the boiler for use in power generation or as process steam.

In this recovery furnace, air is forced into the firebox of the furnace through a large number of air holes from a wind box placed in a position surrounding the firebox. However, black liquor tends to form char deposits around the edges of the air holes, which block air inflow. Previously, workers had to periodically remove the char that had accumulated in the air vents using inefficient and dangerous methods. The alternating cleaning of the air holes and the blocking of the air holes by deposited char changes the amount of combustion air and also changes the air distribution, velocity and pressure. This results in less efficient furnace operation, an unpredictable reduction in the amount of chemicals that can be recovered, and a reduction in the amount of steam generated per fuel. Mechanical rams are known for knocking down deposits and cleaning the air holes in order to ensure air inflow. However, such cleaning is often inefficient and incomplete.

In a preferred embodiment of the invention, the furnace air vents are automatically cleaned by a device that includes a plurality of rods each having a cleaning tip that can be inserted into one of the air vents. These cleaning tips are smaller in size than the air holes in at least one lateral direction. For example, if the air holes are vertically elongated, the cleaning tip would have a width that spans the lateral width of each air hole. Means is provided for advancing the rod to insert the cleaning tip into the air hole and then retracting the rod to withdraw the cleaning tip after cleaning is completed. If the air hole is long in at least one of said sides, for example in the vertical direction, this means causes the rod to be moved in the vertical direction. In this manner, the cleaning tip is moved along the edges of the air holes to remove combustion products or deposits of char.

In a particular embodiment, the attachment means are removably provided on the outer wall of the windbox so that the rod penetrates the windbox in substantially alignment with the air vents of the firebox. This attachment means rotatably and slidably mounts the above-mentioned rod, and preferably includes a tube in which the rod is slidably housed, a fulcrum block through which the tube passes, and a fulcrum block that rotatably supports the rod. and a sealing plate having an aperture disposed between the support block and the wall of the windbox for substantially sealingly receiving the tube. The rod is advanced in its longitudinal direction by means of an actuating cylinder arranged between a transverse member connecting the rod to the outside of the windbox and the above-mentioned attachment means. The means for moving the rod in at least one side, for example vertically in the case of a longitudinally elongated air hole, preferably comprises means for pivoting the rod relative to the mounting means, in particular a transverse arm mounted on said lining tube. and a motor means for driving the horizontal arm to reciprocate.

The device of the present invention operates suitably at regular time intervals based on automatic timing to maintain the air vents substantially clean. As a result, chemical substances can be recovered even better, and thermal energy can be converted into steam or the like more efficiently. Although only one mounting unit in accordance with the present invention is shown and described herein, a plurality of such units will typically be placed around a particular firebox to clean a relatively large number of air holes. Separate equipment units can be operated simultaneously or sequentially.

The apparatus of the present invention can be easily removed from the recovery furnace and adjusted thereto. especially,
The device is mounted on the outside wall of the windbox, with the rod described above extending in line with the air vents of the firebox. The device can be easily removed for repair or use or if liquid escapes from the air vents. The area where the device is installed can be cleaned,
The device can be replaced without damaging the cleaning device itself.

Thus, it is an object of the present invention to provide an improved cleaning device for safely cleaning the air vents of a firebox.

Another object of the present invention is to provide an improved air hole cleaning system that can be easily removed from and adjusted to the recovery furnace.

Still another object of the present invention is to provide an improved cleaning system that increases the efficiency of chemical recovery and increases the efficiency of heat production in recovery furnaces associated with pulp and paper manufacturing processes.

The invention will be explained with reference to the drawings.

As shown in the drawings, particularly in FIG. 1, the cleaning device of the present invention is used in connection with a recovery furnace 10 comprising a firebox of the boiler described above. Through conduit 12, the above-mentioned "black liquor"
is sprayed into the firebox, the chemical substance is deposited on the floor of the firebox as a carbide bed, and the chemical substance-containing odor substance 18 leached from this deposit is collected for subsequent treatment.
A wind box 16 substantially surrounds the firebox, and pressurized combustion air is delivered into the firebox through a number of air holes 20 in a wall 28 of the firebox.

A cleaning device 22 for cleaning the air vents according to the invention is mounted on the outer wall of the windbox so as to be able to clean the air vents in the wall 28 of the firebox.

As shown in more detail in FIGS. 2, 3 and 4, the apparatus 22 has a plurality of rods 24 each provided with a cleaning tip 26, and one air hole 20 in each firebox wall.
be able to be inserted individually. The device described herein includes four rods each having a cleaning tip 26 at the tip. However, fewer or more rods may be provided in each unit. The disclosed unit is convenient to handle and can be easily removed from the furnace and transported when access to the interior of the windbox is required.
The rod 24 is suitably made of stainless steel, and the cleaning tip 26 is made of stainless steel made of chromium molybdenum alloy No. 4140.
form appropriately. High nickel alloy steel may be used as an alternative, but in either case the material must be able to withstand the high temperatures of the firebox, typically 927°C (1700°C). be. In a particular embodiment, the cleaning tip extending widthwise through the corresponding air hole 20 has a rounded tip and is 1 1/4 inches wide. The cleaning tip has a thin vertical section, i.e., a thin thickness, approximately equal to the diameter of the corresponding rod 24 to which the cleaning tip is welded and connected, and the rear end of the cleaning tip is bifurcated as shown. Accommodate Rods as in The thickness of the cleaning tip is significantly smaller than the longer dimension, ie the height, of the air hole 20 through which the cleaning tip passes. Thus, the cleaning tip can be moved vertically to clean along the edge of the corresponding air hole to remove deposited char, as will be explained in more detail below.

In order to rotatably and slidably mount the rod 24, mounting means are removably mounted on the outer wall of the windbox. The mounting means comprises a face plate 38 housed within the frame 32, with which the front opening 31 of the windbox is covered. The frame 32 is arranged obliquely so that the rod 24 projects obliquely downward toward the air hole 20. Appropriately connect the upper edge of the frame 32 to the wall 30 of the wind box.
At the same time, the side wall 34 and the lower wall 36 are extended outwardly so that the front lower end edge of the frame 32 is separated outwardly from the wall 30 of the wind box. When providing the lower groove 40 of the frame 32 and positioning the rod 24 at a position overlapping the air hole,
The face plate 38 is slid along the lower groove 40. When attaching this face plate to the wind box, the lower edge of the face plate is locked in place by a set screw 42, and the washer 48 and frame are secured to each other by a nut 46 attached to a stud 44 protruding from the upper edge of the wind box opening. The upper end edge of the face plate 38 is attached between the face plate 32 and the upper end edge of the face plate 38. This faceplate, which carries the entire device, is thus easily adjustable and can be easily removed from the outer wall of the furnace windbox.

The mounting means is provided with a plurality of fulcrum blocks 74 which are rotatable about a horizontal axis between the bearing pillow blocks 82,84. Screw the bolts 86 into the screw holes at both ends of the fulcrum block. Hole 5 in the center of each fulcrum block
3 is provided to accommodate the tube 52 into which the rod 24 is slid. A set screw attaches each tube 52 to the desired location so that it occupies the proper position within the wind box. The tube 52 is therefore the fulcrum block 7
4 around the axis of the bolt 86.

Bearing support seal plate retainer 78 having a vertically elongated oval opening 92 for receiving tube 52
The bearing pillow blocks 82, 84 are bolted to the face plate 38 through the bolts. The face plate 38 is also provided with a vertically elongated opening 94 through which the tube 52 projects. Retainer 7
8 is thinned at the center to form a track 80, into which the seal plate 76 is slid. A substantially circular hole 90 is provided in the center of the sealing plate 76, and the tube 52 is housed in the hole 90, so that the sealing plate 76 slides along the track 80 when the tube 52 is rotated together with the fulcrum block 74. This construction creates a movable seal at the front end of the windbox to prevent undesired escape of pressurized air. A plurality of springs 88 are disposed between the front side of the seal plate 76 and the rear recess of the fulcrum block 74 to hold the seal plate 76 along the track 80.

A Teflon bushing 102 is inserted into each end of each tube 52 and held in place between the tube end groove, the installed retaining ring 106, and the inner shoulder 104 of the tube 52. The Teflon bushing slidably seals and houses the rod 24 and is configured to be suitable for withstanding relatively high temperatures, such as the heat experienced by the rod and bushing in the windbox. Additionally, the rod conducts heat when the cleaning tip carried by the rod is inserted into the hot fire chamber.

The pipe 52 is made of stainless steel, and a vertical fin 56 is welded to the lower front end. Small tube 11 at the lower end of this vertical fin
A bolt 116 is received in this small tube 118 by welding 8 and attached by a nut 120 to a transverse arm 54 made of angle steel. Transverse arm 54 is provided with a motor 62 and means for rotating rod 24 in combination with this intermediate drive link. Each tube 52 is similarly attached to a transverse arm 54 and an adjustable link arm consisting of female threaded members 70, 72 is pivotally mounted at the center of the transverse arm 54. After a common male thread member is accommodated in the female thread members 70 and 72 and the length of this link arm is adjusted to determine the vertical stroke of the cleaning tip 26, the common male thread member is inserted into the female thread member using the nut 51. Locks on one of the members. The other ends of the link arms 70-72 are removably pivoted to an eccentric crank arm 68, which is mounted to the outer end of a shaft 66 of a reduction gear 64 driven by a motor 62. motor 6
2 rotates the shaft 66 and rotates the transverse arm 54.
is reciprocated, and thus the rod 24 is rotated.
This amount of eccentricity can be adjusted.

Bracket 5 supporting motor 62 and reduction gear 64
Attach to 0. This support bracket 5 is attached to the face plate 38.
Weld 0. Therefore, by loosening the aforementioned set screw 42 and nut 44, the entire unit including the motor drive device can be easily removed from the furnace.

The outer end of each rod 24 is threaded as shown at 108, and nuts 112, 1 are threaded onto a cross member 58 of angle steel in an inverse relationship to the cross arm 54.
14 to attach the outer end of the rod 24. A groove is cut in the lower end of the threaded portion 108 of the rod 24, and this groove accommodates a key 152, which is accommodated in the keyway 154 of the cross member 58 and the lock collar 110 attached to the rear of the cross member 58. The rod is thus held against rotation and the cleaning tip 26 is held in the desired direction, ie across the short dimension of a particular air hole. The rod 24 can be vertically positioned by adjusting the nuts 112, 114 along the threads into position before tightening the nuts to attach the rod to the cross member 58.

The means for sliding the rod forward in the longitudinal direction towards the air hole is provided by an actuating cylinder, in particular the air actuating cylinder 6.
0, the actuating rod 63 of which is connected to the center of the transverse member 58. The other end of the actuating cylinder 60 is rotatably attached to the face plate 38, particularly between the flanges 53 of the bracket 50. Actuation of the actuating cylinder in the direction shown by arrow 61 in FIG. 2 will cause the rod to retract and pull the cleaning tip 26 out of air hole 20, and actuation of the actuating cylinder in the opposite direction will cause the cleaning tip to be removed as shown in the drawing. Insert into the air hole.

A peephole will be provided for the purpose of observing the inside of the wind box. A frame 98 is attached to the face plate 38 so as to overlap the rectangular hole 96, and a heat-resistant Pyrex (trade name) glass plate 100 is attached over the rectangular hole.

When the device of the invention is in the rest position, the actuating rod 63 of the actuating cylinder 60 is projected and the cleaning tip 26 is normally retracted from the air hole 20. Since the temperature in the firebox is significantly higher than in the windbox where the cleaning tip normally resides, the cleaning tip is protected from the excessively high temperatures of the firebox, except for short periods of time.
It also retracts the cleaning tip and prevents the passage of air into the firebox through the air vents 20 from being obstructed. At time intervals, for example about every 20 minutes, the actuating cylinder is actuated to advance the rod and the cleaning tip 26 is inserted into the air hole 20. Next, with the rod extended in this manner, motor 62 is activated to move the structure including transverse arm 54 and tube 52 at a rate of
Rock up and down at cycle speed. The rod is rotated to move the cleaning tip 26 up and down the air hole, removing any accumulated char from the edges of the air hole and creating an unobstructed passage of air into the firebox.
It has been found that this up-and-down rocking can completely remove undesired blockages of deposited carbides. Immediately after the short period of up and down movement, approximately 10-15 seconds, motor 62 is deactivated and actuating cylinder 60 is reactivated to retract the manufacturing chip from the firebox and return to its original position.

5 and 6 show an alternative attachment means 124 for rotatably and slidably attaching the rod 24. In place of the fulcrum block of the embodiment described above, a fulcrum block 122 is provided having a hole 142 to accommodate the tube 52'. Pillow block 8 of the above embodiment
5 instead of end pieces 126, 12
A structure consisting of 8 is provided. Bearing 136 on this end piece
is accommodated, and a bolt 140 is passed through this bearing,
Screw onto the end of the fulcrum block 122. bolt 1
A rod washer 1 is installed between the head 40 and the bearing 136.
Place it appropriately on 38. A back bearing member 130 extends integrally between the end pieces 126 and 128 and is attached to the face plate 38.
The mounting relationship should be fixed. The back bearing member is provided with the cylindrical curved surface 132 which is generally aligned with the rear cylindrical curved surface 160 of the fulcrum block 122. As shown in FIG. 6, the tube 52' is connected to the bearing member 1
These surfaces 13 pass through the large holes 134 of 30.
2 and 160 are in a sliding relationship with each other. This structure provides an effective airtight seal and
2' while substantially preventing air from escaping from the wind box. The structure of FIGS. 5 and 6 does not require the sliding seal plate 76 of the previous embodiment.

Figures 7 and 8 show another cleaning tip for use with the apparatus of the present invention. A tubular member 15 is attached to the lower end of the extensible rod 144, which corresponds to the rod 24 of the embodiment described above.
0 is slidably mounted to allow the tubular member to rotate on the rod. Several longitudinally oriented metal strips 148 at the ends of this tubular member 150
, and arch the metal strip outwardly to contact the edge of the air hole as shown at 146. When rod 144 is moved vertically in the direction shown by arrow 164, metal strip 148 moves into air hole 146.
or ride along the edge of the tubular member 1
50 to alternately engage the metal strips 148 with the edges of the air holes. Whether or not the cleaning tip rotates depends on the relative size and position of the cleaning tip with respect to the air hole. Slide the face plate 38 horizontally relative to the frame 32 to position the cleaning tip in the desired position relative to the air vents. The cleaning tips of Figures 7 and 8 provide a scraping or frictional action along the air holes.

In the embodiment shown in FIGS. 7 and 8, the front end of the rod 144 is threaded and a nut 162 is threaded to hold the rotating member 150 thereon. but,
The rotating member 150 may be attached to the rod 144 within the rotating member 150 using means such as a latch, with the rod 144 attached at the end of the rotating member farthest from the firebox.
It may be attached to 44.

Although the cleaning tip is shown moving up and down to clean the vertically elongated air holes, it is also contemplated that the pivot mounting means for each rod can be rotated 90 degrees to clean the horizontally elongated air holes. The cleaning tip may also be moved horizontally. Alternatively, the device may have horizontal and vertical motion components, for example a circular motion to clean around the edges of a large opening. In either case, the cleaning tip is moved in a direction transverse to the longitudinal direction of the rod to remove the deposited carbide. Since it reciprocates laterally in this manner, an effective abrasion action can be performed on the accumulated carbide.

A number of units of the apparatus of the invention are assembled in a single firebox of the same boiler. The operation of these units is timed by timer means, and the rods can be odorically inserted to quickly clean the air vents while the furnace is running, allowing them to operate almost completely automatically. After moving the cleaning tip up and down several times, the rod is automatically retracted.

The present invention not only improves the operating efficiency of the boiler, but also improves operational safety by eliminating the need for manual cleaning and stabilizing the carbide deposit layer to reduce the risk of hot spots and boiler tube failure.

In the illustrated embodiment, the rod is moved forward to insert the cleaning tip, and then the cleaning tip is moved up and down along the air hole, but after increasing the vertical motion, the motion is reversed to move the cleaning tip in and out. You can move it.

What has been described above is merely an example of the present invention, and the present invention can be modified in various ways within the scope of the claims.

[Brief explanation of drawings]

Fig. 1 is a schematic cross-sectional view of a part of a chemical substance recovery furnace that employs the device of the present invention, Fig. 2 is a perspective view of the device of the present invention, and Fig. 3 is a longitudinal section along line 3-3 in Fig. 2. 4 is an exploded perspective view of the device shown in FIG. 2, FIG. 5 is an exploded view of an alternative mounting device used in the device of the present invention, FIG. 6 is a sectional view of the device shown in FIG. 5, and FIG. The figure is a longitudinal cross-sectional view of an alternative cleaning tip used in the apparatus of the present invention, and FIG. 8 is a cross-sectional view of the cleaning tip of FIG. 7. DESCRIPTION OF SYMBOLS 10... Recovery furnace, 12... Conduit, 16... Wind box, 18... Chemical-containing odor, 20... Air hole, 22... Cleaning device, 24... Rod, 26...
...Cleaning chip, 28, 30... Wall, 31... Opening, 32... Frame, 38... Face plate, 40...
Lower groove, 42... Set screw, 44... Stud,
46...Nut, 48...Washer, 50...Support bracket, 51...Bolt, 52...Pipe, 53...
...hole, 54...horizontal arm, 56...vertical fin, 5
8... Horizontal member, 60... Air actuated cylinder, 62
... Motor, 63 ... Operating rod, 64 ... Reduction gear, 66 ... Shaft, 68 ... Eccentric crank arm, 70, 72 ... Female thread member, 74 ... Fulcrum block, 76 ... Seal plate, 78 ... Bearing support seal plate retainer, 80 ... Raceway, 82, 84 ...
Bearing pillow block, 86... Bolt, 88... Spring, 90... Hole, 92, 94... Opening, 96...
Rectangular hole, 98...Frame, 100...Pyrex glass plate, 102...Teflon bushing,
104...Inner shoulder portion, 106...Retaining ring, 108
...Screw part, 110...Lock collar, 112,
114...Natsuto, 116...Bolt, 118...
...Small tube, 120... Nut, 122... Fulcrum block, 124... Mounting means, 126, 128...
End piece, 130... Back bearing member, 132... Front cylindrical curved surface, 136... Bearing, 138... Lock washer, 140... Bolt, 142... Hole, 144
...Extension rod, 146...Air hole, 148...
Metal strip, 150... tubular member, 152... key, 154... keyway, 160... rear cylindrical curved surface, 162... nut.

Claims (1)

[Scope of Claims] 1. A device for cleaning an air hole in a firebox of a black liquor combustion furnace, comprising a rod having a cleaning tip that can be inserted into the air hole, the cleaning tip having at least one lateral dimension as described above. an attachment means smaller than the air hole and further for attaching said rod; advancing said rod in the longitudinal direction of said rod for inserting said cleaning tip into said air hole and then removing said cleaning tip from said air hole; rod advancement and retraction means for retracting said rod for withdrawal; and moving said rod in at least one lateral direction for moving said cleaning tip against an edge of said air hole to remove residual deposits from said edge. An air hole cleaning device for a black liquor combustion furnace, characterized in that it is equipped with a moving rod movement means. 2. Air vents are arranged in the wall of the firebox of the black liquor combustion furnace;
The firebox is provided with a windbox for supplying pressurized air to the air hole, and the windbox has an outer wall spaced apart from the wall of the firebox. In the air hole cleaning device for a black liquor combustion furnace according to claim 1, which cleans holes, there are a plurality of said rods, each of which is provided with said cleaning tip, and said attachment means. is removably installed on the wind box and rotatably and slidably attaches the rod, and the rod movement means includes means for rotating the rod with respect to the attachment means. , while the cleaning tip is inserted into the air hole,
An air hole cleaning device for a black liquor combustion furnace, characterized in that the rod is moved in at least one side direction before being pulled out from the air hole. 3. The attachment means includes a plurality of lining tubes for slidingly housing the rod, and the means for rotating the rod includes a lateral arm attached to the lining tube and a reciprocating motion by driving the lateral arm. 3. The air hole cleaning device for a black liquor combustion furnace according to claim 2, further comprising a motor means for causing the air holes to be cleaned. 4. The rod advancing and retracting means is provided with a transverse member for coupling the rod on the opposite side of the attachment means from the firebox, and an actuating cylinder disposed between the transverse member and the attachment means. An air hole cleaning device for a black liquor combustion furnace according to claim 2. 5. A lining tube for slidingly housing the rod, a fulcrum block through which the lining tube extends, and bearing means provided on both sides of the fulcrum block for rotatably supporting the fulcrum block;
The mounting means is provided with a face plate for mounting these bearing means, and a laterally slidable seal plate disposed between the bearing means and between the fulcrum block and the face plate. An air hole cleaning device for a black liquor combustion furnace as set forth in claim 2. 6. Black liquor combustion according to claim 5, characterized in that a pressing means is disposed between the fulcrum block and the seal plate in order to maintain the seal plate oriented laterally. Furnace air hole cleaning device. 7. The air hole cleaning device for a black liquor combustion furnace according to claim 5, wherein a frame that accommodates the face plate in a freely adjustable and detachable manner is attached to an outer wall of the wind box. 8. The attachment means includes a lining tube for slidingly housing each of the rods, a fulcrum block having a hole through which the lining tube extends and a rear cylindrical curved surface, and a fulcrum block for rotatably supporting the fulcrum block. The fulcrum block includes bearing means provided on both sides, a face plate for mounting these bearing means, and a back bearing member having the cylindrical curved surface aligned with the rear cylindrical curved surface of the fulcrum block. An air hole cleaning device for a black liquor combustion furnace as set forth in claim 2. 9. said cleaning tips are substantially flat in the horizontal plane in which they are attached to the end of said rod;
3. The air hole cleaning device for a black liquor combustion furnace according to claim 2, wherein the cleaning tip has a contour curved forward in the horizontal plane. 10. The air hole cleaning device for a black liquor combustion furnace according to claim 2, wherein the cleaning tip is adapted to be able to come into contact with a side of the air hole. 11. The air hole cleaning device for a black liquor combustion furnace according to claim 10, wherein the cleaning tip comprises a flat metal member that can rotate on an axis in the longitudinal direction of the rod. 12. An air hole is arranged in the wall of the firebox of the black liquor combustion furnace, and the firebox is provided with a wind box for supplying pressurized air to the air hole, and the air box is arranged in the wall of the firebox of the firebox. The air hole cleaning device for a black liquor combustion furnace according to claim 1, which cleans the air hole of the firebox of a black liquor combustion furnace, which has an outer wall separated from the wall, , each of which is provided with the cleaning tip; the attachment means includes a plate member attachable to the outer wall of the wind box; the rod is removable together with the attachment means from the wind box; An air hole cleaning device for a black liquor combustion furnace, characterized in that the rod advancing and retracting means is disposed on the mounting means and is removable together with the mounting means. 13. The black liquor combustion furnace according to claim 12, further comprising a frame substantially permanently attached to the outer wall of the wind box, and the frame removably houses the plate member. air hole cleaning device. 14. The air hole cleaning device for a black liquor combustion furnace according to claim 13, wherein the frame is provided with a groove at a lower edge in which the plate member is supported.